Assembling and Installing Systems
A-17
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
A.5.2 Rules for the Transition between Lightning Protection Zones
0 and 1
Rule for the Transition 0 <-> 1 (Lightning Protection Equipotential Bonding)
The following measures are suitable for lightning protection equipotential bonding
at the transition between lightning protection zone:
Use grounded, spiralled, current-conducting metal strips or metal braiding, for
example, NYCY or A2Y(K)Y, as a cable shield at the start and end,
and
Lay cable
– in continuous metal pipes that are grounded at the start and end, or
– in ducts of armored concrete with continuous armoring or
– on closed metal cable racks grounded at the start and end,
or
Use fiber-optic cables instead of lightning stroke current-carrying cables.
Additional Measures
If you cannot take the measures listed above, you must install a high-voltage
protector at transition 0 <->1 with a relevant lightning conductor. Table A-2 contains
the components you can use for high-voltage protection of your plant.
Table A-2 High-Voltage Protection of Cables Using Surge Protection Components
Conse-
cutive No.
Connect Cables for ... ... with the Following at Transition
0 <-> 1
Order Number
1 3-phase TN-C system 3 pcs.
Lightning current down conductor
DEHN port
Phase L1/L2/L3
against PEN
900 100*
3-phase TN-S and TT system 4 pcs.
Lightning current down conductor
DEHN port
Phase L1/L2/L3/N
against PEN
900 100*
AC TN-L, TN-S, TT system 2 pcs.
Lightning current down conductor
DEHN port
Phase L1 + N
against PEN
900 100*
2 24 V DC supply 1 KT lightning conductor
type A D 24 V
DSN: 919 253
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